Monday, 11:30 a.m.
If you look at the midmorning infrared satellite image, you can pretty much pick out the genesis area of the storm that will ultimately become the nor'easter we've been warning you about since the second half of last week:
An area of low pressure over central Missouri is spreading rain across the mid-Mississippi Valley, while at the same time the cold front arcing out of the storm to the southwest and west will move swiftly southeastward this afternoon and tonight, triggering some strong to locally severe thunderstorms over southeastern Texas and southern Louisiana. And if you look farther south, you'll see a streamer of Pacific moisture that may well get wrapped back into the circulation of the storm that redevelops just off the Southeast coast late tomorrow and tomorrow and heads up just off the Eastern Seaboard Wednesday and Wednesday night.
The question is not whether or not there will be a storm, but the track and timing of the storm. Once again, the European has been very insistent on a track much closer to the coast than most of its brethren, if you will. But I see with Standard Time now in practice, and earlier model runs, the 12z regional Canadian model is much closer to the coast and is much stronger than the NAM 12z 48-hour forecast. Here's the Canadian surface forecast:
Given how much better the European model performed with Sandy and how insistent it is on this storm deepening rapidly Tuesday night and Wednesday as it crawls up the Eastern Seaboard, it is very hard to bet against it on this upcoming storm. And that means the worst impacts from the nor'easter will be pretty much over the same areas as those hit hardest by Sandy - eastern Virginia up into southern New England.
So, what is to be expected:
1) Gale-force winds. They won't reach hurricane force, as the projected surface pressure difference is about half what it was at one point in Sandy. However, 60-mph gusts are quite possible from the Virginia Capes up to the Long Island coastline and perhaps a few closer to 70 mph. Even without Sandy's impacts from a week ago, that would cause downed trees and power lines. Fortunately, that same tight pressure gradient will not extend all the way back to the mountains, so wind speeds will steadily drop off over the interior of southern New England and back across the mid-Atlantic region.
2) Storm surge. The one really bad thing is the lack of protection from the dunes. On the positive side, there will not have been a hurricane ahead of time to cause long period swells on the ocean ahead of the storm. Furthermore, it comes a little more than halfway between the full moon (last Monday) and the upcoming new moon, so there won't be that extra foot of storm surge as with Sandy. Nevertheless, a few feet will mean some moderate coastal flooding, especially along the Delmarva Peninsula and up the Jersey shore to southern New England.
3) Rain. Early projections are of 1-3 inches, with the gradation going from the coastal areas (3 inches) to areas between the Delaware River/Chesapeake bay and the Susquehanna River (closer to the 1-inch amounts). This will also impact southeastern New England in a similar manner. Given how much it rained with Sandy, the flooding criteria can be met more quickly, so flooding is a real concern from eastern Virginia up into southeastern Pennsylvania and parts of southern New England.
4) Snow. Yes, if the storm tracks as the European suggests, it won't be all rain. There's enough warmth in the boundary layer bring transported inland from off the Atlantic that most places along and especially east of the I-95 corridor will get nothing but rain. West of there, however, with increasing elevation, there can be some snow. The most likely area to get more than 6 inches of snow would be the hills of northwestern New Jersey and into the Poconos, and perhaps through the Catskills and Berkshires into the Green and White Mountains. There's still some debate as to just how much moisture gets to northern New England from the storm.
Behind the storm, it's cold, but not for long. Look at the dramatic change that takes place in the upper levels of the atmosphere by Saturday:
Once beyond this storm, it will warm up this weekend and into the early part of next week, and it looks as if the conditions that have led to Superstorm Sandy and now this nor'easter will not be present this weekend and through next week. That's good news as cleanup and restoration efforts continue throughout the mid-Atlantic and southern New England. The warmer weather this weekend and early next week will definitely be welcomed by most, especially those without power.
Slow changes mean more wet weather across parts of the southern tier of states through the weekend, while a faster jet stream will bring more swift changes to the northern tier states.
Odile will bring flooding rains to parts of Arizona and New Mexico over the next three days, but most of the rest of the country will rather quiet weather.
Much of the country from the Plains to the East Coast will have several more days of very cool weather. Meanwhile, Odile is threatening Arizona and New Mexico with flooding rains later this week.
A strong storm in Quebec combined with a very large high near Montana will result in sweeping changes across the Ohio Valley into the mid-Atlantic and Northeast in the next 24 hours.
The latest surge of heat and humidity into the Midwest will spread to the East tomorrow but be trimmed back to the South later this weekend by the passage of a cold front.
Summer's heat and humidity will still have a period of time to sizzle the rest of the week into the start of the weekend, but a fall-like air mass will invade the northern Plains and Midwest this weekend.